Field of the Invention
The invention relates particulary to a compressing-folding machine with two folding sites formed by one pair of folding rollers and with two folding pockets assigned to them as well as with an intake device. The intake device is arranged in front of the first folding pocket and it includes a carrier roll or several carrier rollers or disks arranged on a shaft which rests on a folding roll in contact with it and forms with it an intake site. A liquid applicator for the stripwise application of a liquid serving for adhesion purposes on given sections of the material to be folded passing through is arranged in front of the intake site and has at least one rotating applicator element and an associated sheet compression element which, part of the time, and intermittently, can be actuated electromagnetically.
A known compressing-folding machine of this kind ,(DE-OS 25 52 216). is provided with a sheet adhesive applicator arranged in front of the intake site. This consists of an adhesive container and a wheel applying the adhesive in the form of strips onto the passing sheets as well as of a sheet compression device with a bow-like sheet lifter which is operated electromagnetically or hydraulically and which presses the sheets for a time against the circumferential area of the adhesive wheel. The adhesive wheel is continually driven and supplied with adhesive. The length of the adhesive strips created on the sheets is determined by the length of time the sheet lifter applies pressure. For controlling the means actuating the sheet lifter, for example an electromagnet, light barriers are provided which scan the passing sheet. When passing through the folding device the sheets which have adhesive applied to them are folded and the adhesive areas are simultaneously compressed.
In another known adhesive applicator which precedes a multiple-folding device (USP 3,784,185) several adhesive strips are generated simultaneously on a paper web. The paper web is subsequently separated into two halves along the longitudinal center and upon passing the folding device in the region of a folding section is adhesively connected, for example pocket-like and brochure-shaped.
Furthermore, a winding device for the preparation of layers of sheets for book binding is known (DE-PS 278 266). This device includes a fabric web wrapped in several layers on a rotating elliptical package in the reel. Layers with an adhesive strip running transversely are provided on a edge of the package in the reel. For the application of the adhesive a continuous rotating adhesive applicator belt is provided which is supplied with adhesive from a supply container. The wound layers are then cut open on the side of the package in the reel opposing the adhesive application edge. With a pinion-type cutter of the package in the reel, the winding edges to which adhesive has been applied, are subsequently slid into a folding device having two compression rollers.
In recent times material to be folded such as printed forms in the form of paper sheets are encountered which at their edges are provided with adhesive strips and/or adhesive spots, whose adhesive in the dry state does not exert an adhesion effect on other dry areas, but only in a wetted state and under pressure will it become connected by adhesion.
With the known adhesive applicators reactivation of the dry adhesive sites is just as readily possible as achieving a permanent adhesion connection of such reactivated adhesive sites when passing through the folding device because, for reactivation of the dry adhesive sites with wetting liquid other application means are required and also because the compression time when passing through the folding device is too short.